1. Field of the Invention
This invention relates to a warp knitted tape for a slide fastener and more particularly to a warp knitted tape for a slide fastener that enables elements to be sewed to a fastener tape easily and accurately and has excellent flexibility and texture.
2. Description of the Related Art
Recently, the slide fastener has been often employed in various kinds of clothes, particularly, clothes ample in flexibility or drape performance or thin clothes. In such a clothes field, naturally, the slide fastener is demanded to have ample flexibility and drape performance or be thin-structured. However, the slide fastener is demanded to have stability in its structure as well as to satisfy such a demand. A knitted fabric is most suitable for the fastener tape having ample flexibility and drape performance or thin-structured from viewpoints of its structure and to secure the stability in structure at the same time, a warp knitting structure capable of controlling stretchability is optimum.
Conventionally, the slide fastener tape having such a warp knitting structure has been well known through, for example, Japanese Utility Model Application Laid-Open No. 51-44405, Japanese Utility Model Application Publication No. 54-35769, Japanese Patent Application Publication No. 55-37241 and Japanese Patent Application Laid-Open No. 5-91908. The warp knitted tapes for the slide fastener disclosed in these publications have specific purposes respectively and their warp knitting structure and yarn handling are devised in various ways to achieve each purpose.
For example, according to the aforementioned Japanese Utility Model Application Laid-Open No. 51-44405, because in the conventional warp knitted tape for the slide fastener, wales formed on the tape have the same hardness, when the tape is sewed to a cloth or the like, the same wale restricts or blocks a smooth piercing of a sewing needle. To solve this problem, a number of constituent knitting yarns in a wale adjacent to a needle piercing portion is reduced to be smaller than that of the constituent yarns in other wales, thereby adaptability of the wale adjacent to the needle piercing portion to the piercing of the sewing needle being heightened. According to the Japanese Utility Model Application Publication No. 54-35769, a wale adjacent to a wale in the most side edge portion of the fastener tape is formed more bulky than the wale in the side edge, and wale grooves disposed on both sides of this bulky wale are formed wider than the wales in the other knitted portion. At the same time, the other knitted portion is constructed with uniform warp knitting structure and the bulky wale is engaged with a concave groove formed in a leg portion of the fastener elements so as to prevent the elements from deflecting therefrom. According to the Japanese Patent Application Publication No. 55-37241, wales are formed with the knitting structure composed of chain knitting and two-needle stitch by use of a non-textured yarn, and two kinds of textured yarns each having a different contraction are knitted in as a weft in-laid yarn in order to obtain a warp knitted tape which does not stretch much and has a excellent texture.
According to the Japanese Patent Application Laid-Open No. 5-91908, the non-textured yarn is used for all knitting yarns in the fastener element attaching portion, the non-textured yarn is used for the chain knitting yarn in the tape main portion and the textured yarn is used for a tricot knitting yarn and weft in-laid yarn so as to achieve different tape thickness in the element attaching portion and tape main body. At the same time, two wales located at its border are formed in the same size and a wale groove composed mixedly of the textured yarns and the non-textured yarns is formed between those wales. Consequently, it is intended to obtain a warp knitted tape which allows an accurate inversion at a specific position when a hidden type slide fastener is finished and which enables its sewing position to be identified easily when it is sewed to clothes.
For the conventional slide fastener having the warp knitting structure, usually, multiple fastener tapes connected with each other by a connecting yarns are knitted at the same time with a large-sized knitting machine and after the knitting is completed, the connecting yarns are cut out. Fastener elements are attached along a side edge of the independent fastener tape manufactured in this way by sewing. However, to cope with manufacturing of multiple kinds with each small production amount in recent years, there is no way but knitting a single tape or a pair or right and left tapes at most with a small knitting machine.
Then, a problem specific for a fastener tape manufactured with the small knitting machine occurs. Usually, the warp knitting structure of the fastener tape knitted in this way is composed of multiple knitting structures, for example, chain knitting, tricot knitting, satin knitting, weft in-laid knitting and the like. If a single body of the fastener tape is knitted with such a knitting structure, both side edges (ear portions) of the same tape are squeezed strongly by the weft knitting yarns, so that a groove between wales in the fastener attaching portion on the side edge is distinguished. Even if it is intended to attach the fastener elements to the fastener tape, as the wale groove forming its sewing line is not evident, the sewing position is deviated and sufficient element attachment strength is not obtained.
To improve productivity, a knitted fastener tape needs to be set thermally on the sewing machine. This thermal setting is carried out under a tension and due to contraction and hardening by heat, its soft texture is lost and a finished product becomes hard. Thus, this fastener tape is not suitable for soft fabric of women's or children's clothes and the like and further, when this fastener tape is sewed to fabric, warpage or stretching occurs, which should be solved. As a result, after a product is completed, sliding resistance of a slider to the fastener elements increases and particularly, there occurs an extreme difference in the sliding resistance at the time of opening/closing the fastener, thereby losing smoothness in the opening/closing operation by the slider.
Therefore, an object of the invention is to provide a warp knitted tape for a slide fastener to be manufactured by a single unit, and more particularly to a warp knitted tape for a slide fastener, having an excellent follow-up performance to object clothes when this fastener tape is sewed thereto, the warp knitted tape allowing an accurate sewing of fastener elements, being soft despite thermal setting and ample in drape performance and allowing a smooth opening/closing by the slider when the fastener elements are attached.